Exhaled pulmonary nitric oxide (NO) may aid in monitoring pulmonary disease. Unfortunately, it has been recognized that, in measuring exhaled pulmonary nitric oxide (NO), there are obstacles that must be overcome. For example, nasal NO concentration can be higher than alveolar NO concentration, and, as a result, contamination with Nasal NO may occur.
One attempt to provide a solution to this problem was as disclosed by Silkoff et al. in a paper entitled “Marked flow-dependence of exhaled nitric oxide using a new technique to exclude nasal nitric oxide,” (AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE, Volume: 155, Issue: 1, Pages: 260-267, Published: January 1997). There a technique was developed to measure pulmonary NO, without nasal NO, by having the subject maintain a positive expiratory pressure (ensuring vellum closure) in an attempt to prevent contamination by nasal NO.
Unfortunately available techniques using exhalation against back pressure of 5 cm H2O or larger can be difficult for people with limited lung expiratory force. Such subjects exhibit an inability to maintain constant exhalation flow for several seconds (e.g., one commercially available device requires between 6 to 10 sec). Further, current commercial devices require pressure of 10-20 cm H2O to perform the measurement, which makes it difficult to get the measurement done, especially in children.
In contrast to known methods, now presented is a new and novel low back pressure mouthpiece for measuring NO that overcomes difficulties in this area not adequately addressed until now.